Re: [PATCH] config: remove explicit undef of unset values

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Dec 16, 2021 at 11:14:30AM +0000, Bruce Richardson wrote:
> Rather than explicitly clearing any setting of undefined values in our
> rte_config.h file, it's better to instead just add a comment that the
> value is not set. Using a comment allows the user to set the value using
> CFLAGS or similar mechanism without the config file clearing the value
> again.
> 
> The text used "<VALUE> is not set" is modelled after the kernel approach
> of doing the same thing.
> 
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
> 
> Although DPDK coding convention forbids use of "//" for comments, using
> regular C comment style makes the config settings less clear, as they can
> be confused with regular comments in the file. Using "//" makes them stand
> out better, so I prefer it. However, if others feel strongly, they can be
> changed to standard.
> 
> Note: this is a resubmission of patch [1] which was part of a rejected
> series. However, the reasons for rejection - values in config being out
> of sync with those used for building apps - are less relevant for
> many, if not all, of these setting, so I believe the benefits for
> testing outweigh the potential downsides. If any setting is likely
> problematic, I can keep the explicit undef for that case in a new patch
> version.
> 
> [1] http://patches.dpdk.org/project/dpdk/patch/20200903144942.671870-2-bruce.richardson@intel.com/
> ---

Ping for review or feedback for this patch. I'd like to see it move forward
into a DPDK release if possible.

/Bruce

>  config/rte_config.h | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/config/rte_config.h b/config/rte_config.h
> index cab4390a97..953216babd 100644
> --- a/config/rte_config.h
> +++ b/config/rte_config.h
> @@ -83,17 +83,17 @@
>  
>  /* ip_fragmentation defines */
>  #define RTE_LIBRTE_IP_FRAG_MAX_FRAG 8
> -#undef RTE_LIBRTE_IP_FRAG_TBL_STAT
> +// RTE_LIBRTE_IP_FRAG_TBL_STAT is not set
>  
>  /* rte_power defines */
>  #define RTE_MAX_LCORE_FREQS 64
>  
>  /* rte_sched defines */
> -#undef RTE_SCHED_CMAN
> -#undef RTE_SCHED_COLLECT_STATS
> -#undef RTE_SCHED_SUBPORT_TC_OV
> +// RTE_SCHED_CMAN is not set
> +// RTE_SCHED_COLLECT_STATS is not set
> +// RTE_SCHED_SUBPORT_TC_OV is not set
>  #define RTE_SCHED_PORT_N_GRINDERS 8
> -#undef RTE_SCHED_VECTOR
> +// RTE_SCHED_VECTOR is not set
>  
>  /* KNI defines */
>  #define RTE_KNI_PREEMPT_DEFAULT 1
> @@ -127,7 +127,7 @@
>  
>  /* i40e defines */
>  #define RTE_LIBRTE_I40E_RX_ALLOW_BULK_ALLOC 1
> -#undef RTE_LIBRTE_I40E_16BYTE_RX_DESC
> +// RTE_LIBRTE_I40E_16BYTE_RX_DESC is not set
>  #define RTE_LIBRTE_I40E_QUEUE_NUM_PER_PF 64
>  #define RTE_LIBRTE_I40E_QUEUE_NUM_PER_VF 4
>  #define RTE_LIBRTE_I40E_QUEUE_NUM_PER_VM 4
> @@ -140,6 +140,6 @@
>  #define RTE_LIBRTE_QEDE_FW ""
>  
>  /* DLB2 defines */
> -#undef RTE_LIBRTE_PMD_DLB2_QUELL_STATS
> +// RTE_LIBRTE_PMD_DLB2_QUELL_STATS is not set
>  
>  #endif /* _RTE_CONFIG_H_ */
> -- 
> 2.32.0
>